| 1 | Development of Mg-based Hydrogen Storage Alloy显示文摘Mg-based hydrogen storage alloys are considered as a promising candidate for hydrogen system because of its lightweight, high storage capacity, low price and rich mineral resources. In detail, we reviewed the preparation and properties of Mg-Ni-based hydrogen storage alloys. All kinds of attempts have been done to improve the hydriding and dehydriding behaviors. It is found that the partial substitution of foreign elements can decrease the hydrogen absorption temperature, especially the substitution of a more electronegative element, such as Al and Mn. Mechanical alloying (MA) and mechanical grinding (MG) are the most effective methods to improve the hydriding/dehydriding kinetics and electrochemical capacity, and decrease the desorption tem- perature, but the corrosion resistance is so poor that the 80% of maximum capacity is lost within ten cycles. Microencapsulation is a useful measurement for improving the corrosion resistance and electrocatalytic activity. In order to improve the properties of the alloys for practical applica- tion, the alloys should have a large number of defects, which give activated sites, subsequently, MA, MG and electroless plating should be used to improve the hydriding/dehydriding kinetics and protect the surface of alloys, respectively. The new composite Mg-based alloys give a new way for the hydrogen storage material to practical application. Furthermore we put forward several problems which will be discussed in future. | Lian bang WANG, Yijing WANG and Hualang YUAM Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071, China Manuscript received June 30, 2000, in revised form September 20, 20001 | 2001 | Journal of Materials Science & Technology2001，17，6： | 1 |
| 3 | Comparison of Three Doses of Gonadotrophin-releasing Hormone Agonist (GnRH-a) in IVF-ET Treatment Cycles显示文摘Objective To investigate the optimal dose of GnRH-a, which is sufficient for down regulation of pituitary without over-suppression of ovarian function in IVF superovulation protocols Methods Sixty patients undertook IVF-ET because of tube factor and /or endometriosis. Patients were divided into three groups randomly. Group A: 25 patients received a single dose of 1.88 mg Decapeptyl; Group B: 20 patients had a single dose of 2.50 mg Decapeptyl; Group C: 15 patients had a single dose of 3.75 mg Decapeptyl. Results The LH levels were 2.00±0.77 IU/L in Group A, 1.05±0.44 IU/L and 0.95 ±0.48 IU/L in Group B and C respectively on the day of starting gonadotropin injection; 1.97±0.76 IU/L in Group A, 0.96±0.42 IU/L and 0.77±0.49 IU/L in Group B and C respectively on the day of hCG administration. The LH levels in Group B and Group C were significantly lower than those in Group A (P<0.01). The mean number of gonadotropin ampoules was higher in Group B (38.05±6.08 ampoules) and Group C (40.0±10.62 ampoules) than in Group A (29.96±4.98 ampoules) (P< 0.01). The duration of stimulation significantly increased in Group B (12.9±1.81 d) and Group C (13.6±2.63 d) as compared with that in Group A (11.24±1.36 d) (P<0.01). There were no differences among three groups in E2 levels on the day of hCG administration, the number of retrieved oocytes, fertilization rate, cleavage rate or pregnancy rate. There was no presence of LH peak in all groups. Conclusion The use of 1.88 mg Decapeptyl provides successful rate similar to 2.50 mg and 3.75 mg Decapeptyl, resulting in the reduced amount of gonadotropin, the duration of stimulation and the cost of treatment. The dose of 1.88 mg Decapeptyl is sufficient for pituitary down-regulation of IVF program for Chinese women. | Xiao-ming ZHAO, Zhu-ping CHEN, Qi-de LIN Reproductive Medical Center, Renji Hospital, Shanghai Second Medical University, Shanghai 20001, China | 2003 | Journal of Reproduction and Contraception2003，14，3： | 0 |
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